Equilibrium volume of Si in the RPA

Overview > bandgap of Si in GW > bandstructure of Si in GW (VASP2WANNIER90) > bandstructure of SrVO3 in GW  > CRPA of SrVO3  > Equilibrium volume of Si in the RPA > List of tutorials

Task

Calculation of the equilibrium lattice constant of Si in the RPA (ACFDT).

Input

POSCAR

system Si
  5.8
0.5 0.5 0.0
0.0 0.5 0.5
0.5 0.0 0.5
2
cart
0.00 0.00 0.00
0.25 0.25 0.25

Calculation

The workflow of RPA total energy calculations consists of five consecutive steps:

• Step 1: a “standard” DFT groundstate calculation with a “dense” mesh of k-points.
• Step 2: compute the Hartree-Fock energy using the orbitals of Step 1. Needs WAVECAR file from step 1.
• Step 3: a “standard” DFT groundstate calculation with “coarse” mesh of k-points.
• Step 4: obtain DFT “virtual” orbitals (empty states). Needs WAVECAR file from step 3.
• Step 5: the RPA correlation energy (ACFDT) calculation. Needs WAVECAR and WAVEDER files from step 4.

In case of metallic systems there is an additional step between Steps 4 and 5, that is beyond the scope of this example.

All of the calculation steps are prepared in the script doall.sh.

Step 1

• DFT groundstate calculation with a “dense” mesh of k-points
• The following INCAR file is used (INCAR.DFT):

ISMEAR = 0 ; SIGMA = 0.05
EDIFF = 1E-8

• The following POSCAR file is used (KPOINTS.12):

12x12x12
 0
G
 12 12 12
  0  0  0

---

Used INCAR Tags

AEXX, AGGAC, ALDAC, ALGO, EDIFF, ISMEAR, KPAR, LHFCALC, LOPTICS, LWAVE, NBANDS, NELM, NKRED, NOMEGA, SIGMA, SYSTEM

Download

Si_ACFDT_vol.tgz

Overview > bandgap of Si in GW > bandstructure of Si in GW (VASP2WANNIER90) > bandstructure of SrVO3 in GW  > CRPA of SrVO3  > Equilibrium volume of Si in the RPA > List of tutorials

Back to the main page.